The Memory Collector by Meg Gardiner

In her job as a forensic psychiatrist, Jo Beckett is used to delving into the lives of the dead to find out if they died of natural or suspicious causes. When she’s called to consult on the case of Ian Kanan, a man who’s barricaded himself on an airplane landing at the San Francisco airport, it’s new for her. Soon, she discovers that Kanan has suffered some kind of brain injury that has prevented him from forming new memories. Basically, his mind resets every five minutes and he can't remember anything that's just happened. He does, however recall everything from before a few days ago--his family, his job, and a mission to destroy those whom he believes have poisoned him. Jo slowly tries to build a picture of Kanan's life and finds out that the situation is way more deadly than she could have ever imagined. The Memory Collector is the second book in the Jo Beckett series. It's full of non-stop action and a fully developed main character. Even better than The Dirty Secrets Club.